There's a meter just below the characters health, that drains when special moves are used, but refills as the character attacks enemies. If an enemy is down, but not defeated, you can hit them from the right distance with a normal attack. Some stages give you alternate route choices. Sometimes your character can pick up a better weapon(specials become more powerful), but it won't last if they lose their current life.

(there are these purple jewels you pick up, and there's a count for them under the right side of the health/special move bar, but I couldn't figure out what they do, and simply transitioning to another section of stage will reset the count to 0)